Integrated steerability array arrangement for minimizing non-uniformity and methods thereof

ABSTRACT

A method for providing steerability in a plasma processing environment during substrate processing is provided. The method includes managing power distribution by controlling power being delivered into the plasma processing environment through an array of electrical elements. The method also includes directing gas flow during substrate processing by controlling the amount of gas flowing through an array of gas injectors into the plasma processing environment, wherein individual ones of the array of gas injectors are interspersed between the array of electrical elements. The method further includes controlling gas exhausting during substrate processing by managing amount of gas exhaust being removed by an array of pumps, wherein the array of electrical elements, the array of gas injectors, and the array of pumps are arranged to create a plurality of plasma regions, each plasma region being substantially similar, thereby creating a uniform plasma region across the substrate.

This application is a divisional and claims priority under 35 U.S.C §120to a previously filed patent application entitled. “INTEGRATEDSTEERABILITY ARRAY ARRANGEMENT FOR MINIMIZING NON-UNIFORMITY”, filed onJun. 24, 2008 by Neil Benjamin, Attorney Docket Number P1543/LMRX-P127,application Ser. No. 12/145,378, which is related to and claims priorityunder 35 U.S.C. §119(e) to a commonly assigned provisional patentapplication entitled “Integrated Steerability Array Arrangement ForMinimizing Non-Uniformity,” by Neil Benjamin, Attorney Docket NumberP1543P/LMRX-P127P1, application Ser. No. 60/947,363 filed on Jun. 29,2007, all incorporated by reference herein.

BACKGROUND OF THE INVENTION

Plasma processing systems have long been employed to process substratesto produce semiconductor devices. During substrate processing,conditions of the chamber have to be closely monitored and carefullycontrolled in order to create a processing environment that is conducivefor creating delicate semiconductor devices. Generally speaking,manufacturers may need to create as processing environment in which theconditions are uniform in order to process a substrate.

Unfortunately, certain conditions that may exist in the processingchamber during substrate processing may cause non-uniformity. Tofacilitate discussion, FIG. 1 shows a simplified block diagram of asubstrate processing environment 100. A substrate 106 is placed on topof an electrostatic chuck (ESC) 108 within a processing chamber 104.Power is delivered into processing chamber 104. In an example, radiofrequency (RF) power 110 may be fed into processing chamber 104 via anelectrostatic chuck. Within processing chamber 104, the RF power mayinteract with gas, which may be delivered into processing chamber 104via a gas delivery system 102, to produce plasma 114, which may interactwith substrate 106 to produce etched semiconductor products.

Ideally, the conditions within processing chamber 104, especially acrosssubstrate 106, are uniform in order to provide a uniform processingenvironment for processing substrate 106. However, due to the design ofprocessing chamber 104, the conditions within the processing chamber areusually non-uniform. In an example, the radial flow of gas may causenon-uniform distribution of gas throughout the processing chamber. Inanother example, the gas exhaust may be non-uniformly pumped out ofprocessing chamber 106 because a pump 112 is usually located away fromthe center of the substrate. Accordingly, the gas exhaust is beingpumped out and downward from the center to the edge of the substrate. Asa result, the gas may be non-uniformly distributed across the surface ofthe substrate. In an example, the gas may be less dense toward the edgeof the substrate.

One method that has been employed to create a more uniform processingenvironment may be performed using a transformer coupled plasma (TCP)source. FIG. 2 shows a simple block diagram of a processing environment200 utilizing a TCP source. Usually, a TCP source produces an inductiveenvironment. Thus, instead of electrodes, set of antenna 202 may beemployed to deliver power to the processing environment.

Within TCP source, plasma 206 may he generated with a doughnut shape toform a toroidal processing region. The toroidal processing regionresults in a radial diffusion profile over a substrate 208. However,even with a radial diffusion profile, the conditions may not he quiteuniform. A larger toroidal processing region may produce a more uniformprocessing environment; however, a larger toroidal processing region mayrequire the chamber to be significantly larger and the dielectric windowto be larger. Accordingly, the cost associated with such an arrangementmay not be financially feasible and the engineering may be significantlymore difficult.

BRIEF SUMMARY OF THE INVENTION

The invention relates, in an embodiment, to an integrated steerabilityarray arrangement for managing plasma uniformity within a plasmaprocessing environment to facilitate processing of a substrate. Thearrangement includes an array of electrical elements. The arrangementalso includes an array of gas injectors, wherein the array of electricalelements and the array of gas injectors are arranged to create aplurality of plasma regions, each plasma region of the plurality ofplasma regions being substantially similar. The arrangement furtherincludes an array of pumps, wherein individual one of the array of pumpsbeing interspersed among the array of electrical elements and the arrayof gas injectors. The array of pumps is configured to facilitate localremoval of gas exhaust to maintain a uniform plasma region within theplasma processing environment.

The above summary relates to only one of the many embodiments of theinvention disclosed herein and is not intended to limit the scope of theinvention, which is set forth in the claims herein. These and otherfeatures of the present invention will be described in more detail belowin the detailed description of the invention and in conjunction with thefollowing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings and in whichlike reference numerals refer to similar elements and in which:

FIG. 1 shows a simplified block diagram of a substrate processingenvironment.

FIG. 2 shows a simple block diagram of a processing environment within aTCP source.

FIG. 3 shows, in an embodiment of the invention, a simple diagramillustrating a top view of an integrated steerability array arrangement.

FIG. 4 shows, in an embodiment of the invention, a cross-sectional viewof an integrated steerability array arrangement.

FIG. 5 shows, in an embodiment of the invention, an example of anintegrated steerability array arrangement with a concentricconfiguration.

DETAILED DESCRIPTION OF EMBODIMENTS

The present invention will now be described in detail with reference toa few embodiments thereof as illustrated in the accompanying drawings.In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present invention. Itwill he apparent, however, to one skilled in the art, that the presentinvention may be practiced without some or all of these specificdetails. In other instances, well known process steps and/or structureshave not been described in detail in order to not unnecessarily obscurethe present invention.

Various embodiments are described hereinbelow, including methods andtechniques. It should he kept in mind that the invention might alsocover articles of manufacture that includes a computer readable mediumon which computer-readable instructions for carrying out embodiments ofthe inventive technique are stored. The computer readable medium mayinclude, for example, semiconductor, magnetic, opto-magnetic, optical,or other forms of computer readable medium for staring computer readablecode. Further, the invention may also cover apparatuses for practicingembodiments of the invention. Such apparatus may include circuits,dedicated and/or programmable, to carry out tasks pertaining toembodiments of the invention. Examples of such apparatus include ageneral-purpose computer and/or a dedicated computing device whenappropriately programmed and may include a combination of acomputer/computing device and dedicated/programmable circuits adaptedfor the various tasks pertaining to embodiments of the invention.

In one aspect of the invention, the inventor herein realized thatsteerability is required in order to achieve more uniform processing. Asdiscussed herein, steerability refers to local uniformity control thatmay be radial author azimuthal control. To achieve steerability, anarray of elements may be implemented.

In the prior art, IC fabricators have attempted to control uniformity bycontrolling the different parameters (e.g., gas flow, gas exhaust, RFenergy distribution, etc.) that may affect the condition of theprocessing chamber. In an example, IC fabricators may employ a Drytectriode machine to control the delivery of power into the processingchamber. A Drytec triode machine includes three electrodes with themiddle electrode being an array of small electrodes. Control may heavailable to direct the flow of power through the middle electrode.However, even with the Drytec triode machine, non-uniformity remains aproblem because the Drytec triode machine does not provide localdelivery of the other parameters, such as gas flow and gas exhaust.

As aforementioned, a traditional plasma system may be configured to havea single gas injector delivering gas into the processing chamber and asingle pump for removing the gas exhaust. IC fabricators havemanipulated the parameters in an attempt to create a more uniformprocessing environment. In an example, a process engineer may controlthe speed of the gas flow in an attempt to generate to more evendistribution of gas. Manipulating the different parameters in order toproduce more uniform plasma is as tedious and time-consuming process andtends to require a high degree of precision and involve balancing manysources of non-uniformity against one another while maintainingdesirable etch rate, etch profile, selectivity, and other parameters.

In accordance with embodiments of the invention, an integratedsteerability array arrangement is provided for enabling local controlduring substrate processing. Embodiments of the invention providesteerability by creating individually controlled set of processingregions.

In an embodiment of the invention, the integrated steerability arrayarrangement may include a variety of configurations. The configurationsmay be symmetrical patterns in order to provide a more uniformprocessing environment, in an embodiment. Examples of configurations mayinclude, but are not limited to, a rectangular pattern, a circularpattern, a hexagonal pattern, and the like.

In an embodiment of the invention, the integrated steerability arrayarrangement may include an array of electrical elements, an array of gasinjectors, and/or an array of pumps interspersed among one another tocreate individually controlled set of processing regions. Consider thesituation wherein, for example, power is delivered through an array ofelectrical elements and gas is being injected into the processingchamber through an array of gas injectors. The array of electricalelements and gas injectors may be arranged in a manner that facilitatesthe productions of a plurality of small plasma regions that areself-similar over the substrate. Thus, the amount of power and/or gasthat may be required to create a uniform processing environment acrossthe substrate being processed may be locally controlled.

Further, to maintain the uniform condition of the processingenvironment, an array of pumps or one or more pumps, each with aplurality of pumping ports connected to a manifold, may be interspersedamong the arrays of electrical elements/gas injectors in order tofacilitate local removal of gas exhaust, in an embodiment. Each port maybe fixed or may be controllable (e.g., via a valve). Unlike the priorart, by having the pumps located in close proximity to the gasinjectors, the gas may be pumped in and out locally instead of beingpumped radially outward from the position typically above or under thesubstrate. Also, the speed of the pumps may be individually controlled,enabling the flow of gas exhaust to be adjusted according to the need ofeach small plasma region.

The features and advantages of the present invention may be betterunderstood with reference to the figures and discussions that follow.

FIG. 3 shows, in an embodiment of the invention, a simple diagramillustrating a top view of an integrated steerability array arrangement.An integrated steerability array arrangement 300 may include adielectric plate 302 with an array of electrical element pairs, such asa pair of electrical elements 304 and 306, embedded into dielectric,plate 302. In an embodiment, the array of electrical element pairs maybe a pair of capacitive elements (e.g., parallel plates). In anotherembodiment, the array of electrical element pairs may be a pair ofinductive elements (e.g. antenna). The array of electrical element pairsmay be arranged in a plurality of configurations, such as a ladderarrangement. In an example, each electrical element pair is arranged ina push-pull ladder arrangement in order to create a balanced powerarrangement.

Intersperse among the array of pair of electrical elements are arrays ofgas injectors from which gas may be delivered into the processingchamber. in an example, pair of electrical elements 306 may include anarray of gas injectors (e.g., 308, 310, 312, etc). By having the arrayof gas injectors interspersed between the array of electrical elementpairs, the amount of gas and power delivered into the processing chambermay be individually controlled during substrate processing.

In the prior art, due to the nature of the substrate and due to theconfiguration of the processing chamber (e.g., edge ring), the plasmatends to be less uniform toward the edge of the substrate. Since priorart configuration may not include an array of gas injectors, the processengineer may not be able to locally control the amount of gas beingdelivered into specific areas of the processing chamber. With the arraysof electrical element pairs and/or gas injector pairs, steerability maybe performed to direct the flow of power and/or gas into specific areasof the processing chamber. In an example, the processing region aroundgas injector 310 (such as the edge of the substrate) may require moregas and/or power than the processing region around gas injector 312(such as the center of the substrate). With the integrated steerabilityarray arrangement, the flow of gas and/or power may be steered in orderto create a more uniform processing environment.

In an embodiment, a set of pumps may be interspersed within theintegrated steerability array arrangement. In an example, a set of pumpsmay be positioned between an array of electrical element pairs. In anembodiment, the set of pumps may be an array of pumps (314 a, 314 b, 316a, 316 b, 316 d, 318 a, 318 b, 318 c, 318 d, 318 e, 320 a, 320 b, 320 c,322 a, and 322 b or one or more pumps, each with a plurality of pumpingports connected to a manifold. Each port may be fixed or may becontrollable (e.g., via a valve). By having the set of pumps locatedwithin close proximity to the array of gas injectors, the gas exhaustmay be removed from the processing chamber in a manner that produce amore uniform processing environment. In the prior art, a pump may belocated near the edge of the substrate resulting in gas exhaust beingpumped outward and downward from the substrate, thereby creating aprocessing environment in which the gas is less dense at the edge of thesubstrate. However, with a set of pumps, the pump speed may becontrolled locally enabling the amount of gas exhaust being removed tobe individually controlled, thereby maintaining a balance of gas withinthe processing environment. In an example, due to the inherent nature ofthe processing chamber, gas tends to be less dense near the edge of asubstrate. Thus, the pumps in the area around the edge of the substratemay be pumping at a slower speed than the pumps toward the center of thesubstrate in order to reduce the amount of gas being removed at theedge.

FIG. 4 shows, in an embodiment of the invention, a cross-sectional viewof an integrated steerability array arrangement 400. Consider thesituation wherein, for example, a substrate 402 is being processed.Power (e.g., RF power, microwave power, etc.) may be delivered into theprocessing chamber via an array of antenna (as shown by antenna 404,406, 408, and 410). Interspersed among the array of antenna is an arrayof gas injectors (412, 414, 416, and 418) from which gas may bedelivered into the processing environment to interact with the power tocreate plasma. Similarly, an array of pumps (428, 430, 432, 434, and436) may be interspersed among the arrays of antenna. Each pump has aplurality of pumping ports (428 a, 430 a, 432 a, 434 a, and 436 a).

With an integrated steerability array arrangement, steerability isprovided thereby enabling the flow of power, gas, and gas exhaust to belocally controlled. In other words, the flow of power, gas, and gasexhaust may be adjusted such that a uniform processing environment isprovided over the different regions (450, 452, 454, and 456) ofsubstrate 402 to enable a more precise and accurate processing of thesubstrate.

As aforementioned, integrated steerability array arrangement may be indifferent configurations. FIG. 5 shows, in an embodiment of theinvention, an example of an integrated steerability array arrangementwith a concentric configuration. Integrated steerability arrayarrangement 500 may include an array of electrical elements (e.g., 502,504, 506, etc.) arranged as concentric rings with a center. Interspersedamong the array of electrical elements are an array of gas injectors(e.g., 508, 510, 512, etc.) and an array of pumps (e.g., 514, 516, 518,etc.). Steerability may be achieved by adjusting the flow of power, gas,and gas exhaust locally. With an integrated steerability arrayarrangement, each component of the arrays may be individually adjustedto create small plasma regions that are self-similar across the surfaceof the substrate.

As can be appreciated from the foregoing, embodiments of the inventionenable an integrated local control arrangement to effectively create amore uniform substrate processing environment. By implementing anintegrated steerability array arrangement, steerability may be employedto direct the flow of power, gas, and gas exhaust within the processingchamber. With steerability, local controls are provided creating a moreuniform processing environment. Thus, different regions on a substrateare self-similar enabling more precise, accurate, and uniform processingof the substrate. Accordingly, with a more uniform processingenvironment, overall cost-savings may be achieved due to less defectivedevices being created.

As can be appreciated from the foregoing, the arrays of electricalelements are self-similar arrays, in an embodiment. In other words, thearrays of electrical elements enable local control of the plasma tocreate the same processing condition across the substrate. In anotherembodiment, the conditions may be intentionally manipulated to presentdifferent processing, conditions at different portions of the substrate.In so doing, non-uniformity problems that are common in the prior art,such as the substrate edge experiencing a different plasma than thecenter of the substrate, may be fixed by local control compensating.Also, if the non-uniformity of the incoming substrate is known (e.g.,via lithography), the local control can be adjusted such that theoutgoing substrate is more uniform than the incoming substrate.

There may still be a residual non-uniformity at the edge. Thisnon-uniformity may be confined to the scale length of the elementsdisposed close to the edge and may be addressed by other techniques.

While this invention has been described in terms of several preferredembodiments, there are alterations, permutations, and equivalents, whichfall within the scope of this invention. Although various examples areprovided herein, it is intended that these examples be illustrative andnot limiting, with respect to the invention.

Also, the title and summary are provided herein for convenience andshould not be used to construe the scope of the claims herein. Further,the abstract is written in a highly abbreviated form and is providedherein for convenience and thus should not be employed to construe orlimit the overall invention, which is expressed in the claims. If theterm “set” is employed herein, such term is intended to have itscommonly understood mathematical meaning to cover zero, one, or morethan one member. It should also be noted that there are many alternativeways of implementing the methods and apparatuses of the presentinvention. It is therefore intended that the following appended claimshe interpreted as including all such alterations, permutations, andequivalents as fail within the true spirit and scope of the presentinvention.

1-13. (canceled)
 14. A method for providing steerability in a plasmaprocessing environment during processing of a substrate, comprising:managing power distribution during said processing of said substrate bycontrolling power being delivered, into said plasma processingenvironment through an array of electrical elements; directing gas flowduring said processing of said substrate, said directing includingcontrolling amount of gas flowing through an array of gas injectors intosaid plasma processing environment, individual ones of said array of gasinjectors being interspersed between said array of electrical elements;and controlling gas exhausting during said processing of said substrateby managing amount of gas exhaust being removed by an array of pumps,wherein said array of electrical elements, said array of gas injectors,and said array of pumps are arranged to create a plurality of plasmaregions, each plasma region of said plurality of plasma regions beingsubstantially similar, thereby creating a uniform plasma region acrosssaid substrate.
 15. The method of claim 14 wherein said array ofelectrical elements is arranged on a dielectric plate.
 16. The method ofclaim 15 wherein said array of electrical elements is an array ofelectrical element pairs.
 17. The method of claim 16 wherein said arrayof electrical element pairs is an array of capacitive element pairs. 18.The method of claim 15 wherein said array of electrical element pairs isan array of inductive element pairs.
 19. The method of claim 15 whereinindividual ones of said array of electrical element pairs is arranged ina push-pull ladder arrangement.
 20. The method of claim 19 wherein saidarray of electrical elements is arranged as concentric rings with acenter and interspersed between said array of electrical elements issaid array of gas injectors and said array of pumps.
 21. The method ofclaim 17 wherein said array of capacitive element pairs is an array ofparallel plate pairs.
 22. The method of claim 18 wherein said array ofinductive element pairs is an array of antenna pairs.
 23. The method ofclaim 14 wherein said array of electrical elements, said array of gasinjectors, and said array of pumps form an integrated array arrangementthat has a symmetrical pattern.
 24. The method of claim 14 wherein saidarray of electrical elements, said array of gas injectors, and saidarray of pumps form an integrated array arrangement that has aconcentric configuration.
 25. The method of claim 14 wherein said arrayof electrical elements, said array of gas injectors, and said array ofpumps form an integrated array arrangement that has a rectangularconfiguration.
 26. The method of claim 14 wherein said array ofelectrical elements, said array of gas injectors, and said array ofpumps form an integrated array arrangement that has a polygonalconfiguration.
 27. A method for providing steerability in a plasmaprocessing environment during processing of a substrate, comprising:managing power distribution during said processing of said substrate bycontrolling power being delivered into said plasma processingenvironment through an array of electrical elements; directing gas flowduring said processing of said substrate, said directing includingcontrolling amount of gas flowing through an array of gas injectors intosaid plasma processing environment, individual ones of said array of gasinjectors being configured to be independently controllable; andcontrolling gas exhausting during said processing of said substrate bymanaging amount of gas exhaust being removed by an array of pumps,wherein said array of electrical elements, said array of gas injectors,and said array of pumps are arranged to create a plurality of plasmaregions, each plasma region of said plurality of plasma regions beingsubstantially similar, thereby creating a uniform plasma region acrosssaid substrate.
 28. The method of claim 27 wherein said array ofelectrical elements, said array of gas injectors, and said array ofpumps form an integrated array arrangement that has a symmetricalpattern.
 29. The method of claim 27 wherein said array of electricalelements, said array of gas injectors, and said array of pumps form anintegrated array arrangement that has a concentric configuration. 30.The method of claim 27 wherein said array of electrical elements, saidarray of gas injectors, and said array of pumps form an integrated arrayarrangement that has a rectangular configuration.
 31. The method ofclaim 27 wherein said array of electrical, elements, said array of gasinjectors, and said array of pumps form an integrated array arrangementthat has a polygonal configuration.
 32. The method of claim 27 whereinindividual ones of said array of electrical elements are configured tobe independently controllable.
 33. The method of claim 27 wherein saidarray of electrical elements is arranged as concentric rings with acenter and interspersed between said array of electrical elements issaid array of gas injectors and said array of pumps.